Exactly as the topic heading states, I'm replacing the output pot on the front end of the MP1 and the rear output jacks. Any recommendations on brands or even specific models you guys have used in the past?

Myself, I don't even bother with using stock-style plastic frame jacks for the Outputs on the back. I just use the standard open-frame jacks mounted to the rear panel with insulating washers. Then they are wired to the circuit board. A little tighter fit but it does work. iirc there's a Mod Doc about it but if you can't find it I can get that for you later this evening.

I did the rear input mod on my first MP1 (it sounded like that thing so it's as well I sold it ).

I replaced the front input with a switchcraft knock off guitar input, wired it to the board then ran wires to the back input. The front one was switching so it would shut off the rear anytime a jack was plugged into the front.

Here is a guide which might help, it looks different from the guide I followed to be honest, looks more in detail

This mod influenced my to do my own mod on my Boss GT5 and replace a shit microphonic inut with a sturdy cliff socket. It didn't fit to the pcb so you flip it round and have the tabs in the air and solder wires to them accordingly to the pcb itself, just like the input mod.